Circuit Ampacity for temporary generator

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philly

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I am trying to determine the required circuit ampacity for a 4.16kV 800kW temporary roll-up generator that will connect to a switchgear interface.

I know NEC 445.13 provides a required circuit ampacity of 115% of nameplate current but I wanted to get clarification on a few items.

I believe this unit may have its own internal protective device. If that is the case can I just base the circuit ampacity off of that protective device side and make the interface breaker in the switchgear have the same rating?

If I cannot get unit's protective device rating can I simply take the nameplate current and apply the 115% to determine circuit ampacity and rating/setting for switchgear interface breaker?

If I have no information available can I simply use the 800kW with a .8pf to get a kVA rating and corresponding rated current and then apply the 115% for circuit ampacity?

What section do I reference for the size of the ground cable between the generator and the switchgear enclosure. Would this be 250.122 if the neutral is not being used on the generator?
 
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